While most DWI cases involve breath tests, defendants may also be charged with drunken driving based on the result of blood tests.
As a general rule, only a physician, registered nurse or a phlebotomist qualified by the state can draw the blood for purposes of determining blood alcohol concentration. Additionally, there are many requirements concerning the way these tests are to be taken and the manner in which samples are to be transported, preserved, secured, and analyzed.
The method used to determine blood alcohol concentration is called “gas chromatography.” The equipment used is capable of isolating and identifying a wide range of drugs, including alcohol.
An experienced DWI defense attorney will demand supporting documents (called “discovery”) from the prosecutor, including: all documents, records, materials or other items related to the chain of custody of samples and/or other specimens taken from defendant; copies of all maintenance repair records of the subject testing equipment; qualifications of any individual(s) performing the analysis of defendant’s specimen; analytical method used to perform all test of the specimen; raw data on all quality control tests performed during the subject analysis; any records related to quality control tests related to the subject laboratory for the six-month period prior to the analysis of defendant’s specimen; raw data of the analytical tests performed on the specimen (lab worksheet); work list for all other samples analyzed at or around the time defendant’s sample was analyzed, including description of specimens, refrigerator log, including records of temperature, other items stored and any person entering refrigerator during the time defendant’s specimen was stored therein; and operating manual for all instruments utilized to test the subject sample(s).